Technical Field
The present disclosure relates to a plastic lens element, a plastic annular optical element and a lens module. More particularly, the present disclosure relates to a plastic lens element, a plastic annular optical element and a lens module which are applicable to portable electronic devices.
Description of Related Art
In order to satisfy the specification of the lens module featured with the large aperture and high resolution, the plastic lens element has the trend of being thinner. The thin lens element requires a larger optical effective portion, so that the outer diameter of the thin lens element is required to be larger.
FIG. 11 is a schematic view of a conventional plastic lens element 80. In FIG. 11, the conventional plastic lens element 80 easily shrinks unevenly after molding so as to warp. For example, before molding, the conventional plastic lens element 80 under simulation has a central line x along a radial direction of a central axis z. However, after molding, the conventional plastic lens element 80 actually has a central line x1 being bended along the radial direction of the central axis z, and thereby the quality of an optical effective portion of the conventional plastic lens element 80 would be affected.
FIG. 12A is a schematic view of a conventional plastic lens element 90, and FIG. 12B is a top view of the conventional plastic lens element 90. In FIG. 12A and FIG. 12B, the conventional plastic lens element 90 serves as a solution for the injection molding process of the conventional plastic lens element aforementioned in the last paragraph. The conventional plastic lens element 90 has the design of a gate trace 93 of a narrow runner for an optical effective portion featured with the better quality. However, when a plurality of the strip structures 91 are added on the conventional plastic lens element 90, the conventional plastic lens element 90 easily has an uneven shrinkage along a shrinkage direction SD, and thereby the design purposes of the gate trace 93 of the narrow runner for the conventional plastic lens element 90 as a thin lens element would not be achieved. A Fine line 95 would occur on the surface of the optical effective portion so as to affect the optical features of the conventional plastic lens element 90.
In addition, if each of the strip structures of the conventional plastic lens element is divided into segments, it will result in increasing unnecessary additional partial thickness of the conventional plastic lens element, spending more time for mold machining, and increasing unnecessary cost.
Given the above, how to improve a plastic lens element and a plastic annular optical element, so as to provide structural solutions therefor to satisfy the design specification of a lens module featured with the large aperture and high resolution, has become one of the important subjects.